The entire disclosure of Japanese Patent Application No. 2006-145844, filed May 25, 2006 is expressly incorporated herein by reference.
1. Technical Field
The invention relates to a liquid ejecting apparatus and, more particularly, to a liquid ejecting apparatus capable of controlling the discharge of liquid droplets using a plurality of driving signals.
2. Related Art
Typically, a liquid ejecting apparatus has a liquid ejecting head capable of discharging liquid droplets of various liquids. An example of such a liquid ejecting apparatus is an ink jet recording apparatus, or printer, with an ink jet recording head (hereinafter, referred to as a recording head) which discharges liquid ink droplets from the recording head.
A liquid ejecting head is typically provided with pressure chambers such that a change in the pressure of the liquid contained in the pressure chamber occurs by actuating a pressure generating unit such as a piezoelectric vibrator. The ink then travels through a series of passages extending from the pressure chambers to a series of nozzles where it is discharged as ink droplets.
In recent years, ink jet recording apparatuses have been developed wherein a plurality of driving signals, comprised of discharge pulses which correspond to the different volumes of the ink droplets are sent to the piezoelectric vibrators (for example, see JP-A-2005-088582 (FIG. 5)). Advantageously, this allows for multi-valued gradation and improved speed in the recording process.
In recent years, however, the thicknesses of partitions between the pressure chambers has been decreased in order to decrease the weight and size of the recording head. As a result, a pressure vibration occurring in ink in one pressure chamber can reach the pressure chamber of a second nozzle and the velocity of ink droplets as they are being discharged from the second nozzle may be decreased. Particularly, when the ink droplets are discharged from adjacent nozzles using discharge pulses generated from different driving signals, there is a possibility that discharge of one nozzle will influence the discharge of the other nozzle.
When the velocity of the discharged ink droplets is decreased, the droplets may enter a mist state and fail to successfully hit the discharge target, thereby deteriorating the quality the resulting image.